This invention relates to industrial operating heads adapted to travel through successive operating cycles that generally include extension and retraction to and from a space within which predetermined operations are to be performed.
More particularly, the invention relates to an apparatus for moving the operating head automatically through the desired cycle, and especially where the head travels between the platen of a die-casting machine after each casting operation. In the die-casting application, the operating head may perform certain functions such as spraying a lubricant on the die surfaces and emitting an air blast to remove flash formed at parting lines.
In many industrial forming processes, such as the molding, die-casting, drawing and forging of metals and other materials, it is common practice to apply a lubricant to the working surfaces between each forming cycle. At the same time, while the mold or die sections are separated, other operations are often performed, such as blowing air against the forming surfaces to remove any residual flash that may remain around the die cavities, and also blowing air or spraying air and water to cool surfaces which are difficult to cool with the integral circulating cooling system normally provided. The lubricant, which is generally in liquid or powdered form, improves the flow of the metal or other material being formed, reduces wear of the working parts, and facilitates removal of the newly formed product from the mold or die. Often, two different types of liquid are to be sprayed during an operating cycle.
To apply the lubricant automatically, and thus avoid the necessity of having a worker move between the opposed platens of an open die or mold between cycles, mechanical reciprocating devices are commonly used. These devices move a spray head past the surfaces of the mold or die to be lubricated while the platens are separated, and spray intermittently so as to apply the lubricant to the desired surfaces. Such devices commonly have air blast nozzles as well to help cool various working parts and also to remove flash.
When the forming cycles are repeated quite rapidly, it is necessary to move the spray head and associated equipment at high speed between the open die sections, since the dwell time during which the mold or die platens remain open after removal of the newly formed part is relatively short. The state of the art in this field is shown by the following patents.
______________________________________ Patentee Issued ______________________________________ U.S. Pat. No. 4,293,024 Kikuchi et al. Oct. 6, 1981 4,214,704 Nagai July 29, 1980 4,041,899 Wolfe and Heath Aug. 16, 1977 3,998,388 Alagna Dec. 21, 1976 3,870,164 Haase March 11, 1975 3,699,592 Miller June 13, 1972 3,544,355 Ott Dec. 1, 1970 3,525,382 Devol Aug. 25, 1970 3,522,838 Ott Aug. 4, 1970 3,482,652 Stone III Dec. 9, 1969 3,463,399 Ott Aug. 26, 1968 3,393,658 Ott July 23, 1967 2,929,564 Stone III March 22, 1960 2,695,592 Szczepanski Nov. 30, 1954 2,344,905 Short March 21, 1944 German Patent Specification 1,296,743 Jan. 22, 1970 and the following publications: Acheson Technical Brochure, entitled "Dag Swing Arm Reciprocator for automatic spraying of pressure die casting dies"; Rimrock Corp. technical data sheet for Reciprocator Model 001, Model 002, Manifold and Nozzle Assemblies Model 104 Rimrock Corp. technical report No. 3 entitled "How problem tooling runs more profitably at Kolsters Tool and Die" G-W Plastics Engineers, Inc., technical bulletin 300R ______________________________________
Most of the prior art devices in the references listed above utilize fluid drive means, such as hydraulic or pneumatic cylinder and piston assemblies.
A few devices utilize purely mechanical drive means, such as screw and ball type drive as shown in U.S. Pat. No. 4,041,899; however, in each case the device, in order to provide the necessary length of travel of the operating head, is exceptionally long, and since most are mounted over the machine on molding apparatus to be serviced, considerable overhead height is required, at least a height equal to the length of the reciprocating path of travel of the operating head. May installations, however, do not have sufficient height overhead and thus are severely limited as to utilization of the particular space.
In many die casting machines, provision is made for placing a core in the cavity defined by the two die sections. The core is supported at approximately the parting line by a "core-pull" cylinder mounted on the movable die section and extending above the top of the section. After a product is cast in the die cavity with the core in place, the core is lifted out of the casting by the core pull cylinder to permit the casting to be extracted.
Accordingly, reciprocating lubricant spraying devices of prior art design must be supported in a retracted position well above the core pull cylinder when the movable die is in its closed operating position. This is because prior art spraying devices reciprocate in a vertical path and do not permit the spray head to move to a laterally offset position relative to the upward projection of the space between the open die sections.
For the same reason, the length of the stroke of prior art reciprocating devices needs to be extremely long to reach downward to the level of the die cavity.
Another problem that has been encountered with some prior art devices is that spray heads are usually raised directly upward to a position immediately above the die sections and molded products may be spoiled by "after-dribble" of a mold release agent from a spray head of inferior design. The drops from such a spray head damage the appearance and quality of the molded product.
For the reasons described, it is particularly desirable that in the rest position, the spray head be moved to a location that is spaced laterally from the upward projection of the working area.
The device of the present invention reduces the difficulties indicated above, and affords other features and advantages heretofore not obtainable.